dbms_lob.substr...?

 Hi All,

Please find the sample XML file data,

<FileName>1.txt</FileName>
<FileContentType>text/plain</FileContentType>
<FileData>3C5472616E73616374696F6E3E0D0A2020203C5472616E734374783E0D0A2020202020203C5472616E73616374696F6E47726F75703E54414C454E545F4D474D543C2F5472616E73616374696F6E47726F75703E0D0A2020202020203C5072736E4A6F624E61</FileData>
----------------
---------------

By using dbms_lob.substr we can achieve may be.

My requirement is that,either pickup the <FIleData> value or erase the value of <FIleData> node.

can anyone tell me how can i achieve my requirement?

<FileData> node value not fixed it varies each time.